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The redox behaviour of tetrakis(triphenylphosphine)-platinum(0) [Pt(TPP)4], tetrakis(triphenylphosphine)-palladium(0) [Pd(TPP)4] and tetrakis(triphenylphosphine)-nickel(0) [Ni(TPP)4] has been studied in N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), acetonitrile (AN), propanediol carbonate (PDC), N,N-dimethylthioformamide (DMTF) N-methylpyrrolidine-2-thione (NMTP) and nitromethane (NM). The platinum complex was found to undergo irreversible two electron oxidations with partial or complete loss of the ligands in all solvents but nitromethane. The palladium complex was also oxidized to the divalent form in the solvents studied except inPDC andNM where the complex was found to be polarographically inactive; Ni(TTP)4 was reversibly or almost reversibly oxidized to a movovalent form inDMF, AN andDMTF followed by an irreversible oxidation to a divalent complex. Direct oxidation to the divalent form occurred inDMSO, no oxidation was observable inNMTP andPDC, decomposition took place in nitromethane. The half-wave potentials were recorded versus bisbiphenylchromium iodide (BBCr)I as an internal standard. The influence of the solvents on the redox behaviour and the dissociation of ligands is discussed.

Mit 1 Abbildung  相似文献   

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An experimental study has been made of thermal electron attachment to the transition-metal trifluorophosphine complexes Ni(PF(3))(4) and Pt(PF(3))(4) using a flowing-afterglow Langmuir-probe apparatus. Both complexes are efficient at electron attachment, although the rate constants are somewhat less than collisional. The rate constant for electron attachment to Ni(PF(3))(4) is 1.9 x 10(-7) cm(3) s(-1) at room temperature, about a factor of 2 less than collisional. The activation energy is 39+/-5 meV for the attachment reaction. The rate constant for electron attachment to Pt(PF(3))(4) is 5.4 x 10(-8) cm(3) s(-1) at room temperature, and the activation energy is 84+/-8 meV. For both complexes, a PF(3) ligand is lost on electron attachment, and only the M(PF(3))(3)(-) ion is observed in the negative-ion mass spectrum. Density functional calculations were carried out on Ni(PF(3))(4) and various fragments in order to describe the thermochemistry of the attachment reaction.  相似文献   

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Force constants for a SVFF approximation have been obtained for the compounds Ni(PF3)4, Pd(PF3)4 and Pt(PF3)4 using the FG matrix method and vibrational assignments (A1, E and F2 symmetry species) on the basis of regular tetrahedral symmetry, point group Td. Six primary force constants involving bond stretching and bond angle changes and five interaction force constants were used to simultaneously fit the observed wavenumbers. The PF stretching force constant differs by only ± 3% for all three compounds and for the free ligand, PF3. The metal—phosphorus stretching force constant, however, increases significantly in the order Ni < Pd < Pt, and is 65% larger for Pt(PF3)4 than for Ni(PF3)4. These changes are discussed in terms of the metal—phosphorus—fluorine bonding in M(PF3)4 compounds.  相似文献   

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Ni(PF3)4 ( 1 ) tauscht mit Lithiumorganylen und Grignard-Reagentien Fluor gegen Organyl-Gruppen aus, wobei die Komplexe ( 10–32 ) Ni(PF3)4?n(PF2R)n (n = 1, 2 und 3), Ni(PF3)3(PFR2), Ni(PF3)2(PF2R)(PFR2) und Ni(PF3)3(PR3) (R = organ. Rest) gebildet werden. Für den Reaktionsablauf wird ein Vierzentren-Synchron-Mechanismus vorgeschlagen. Fluorine Exchange in Trifluorophosphane Metal Complexes. X. Reactions of Tetrakis(trifluorophosphane)nickel(0) with Metal Organyls The fluorine atoms in Ni(PF3)4 ( 1 ) can be partially substituted by organyl groups yielding the complexes ( 10–32 ) Ni(PF3)4?n(PF2R)n (n = 1, 2 and 3), Ni(PF3)3(PFR2), Ni(PF3)2(PF2R)(PFR2) and Ni(PF3)3(PR3) (R = organyl group). The mechanism of these peripheric reactions is discussed by assuming a four centered type intermediate.  相似文献   

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Chloro(trifluorophosphane)gold(I): [Au(PF3)Cl] X‐ray quality crystals of [Au(PF3)Cl] (orthorhombic, Pnma) are obtained from a toluene / pentane solution at 6 °C. According to the result of the X‐ray structural analysis, [Au(PF3)Cl] contains an almost linear F3P‐Au‐Cl unit. The shortest Au‐Au contacts between two of these units are 3.3495(9) Å.  相似文献   

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Tetrakis(triphenylphosphoraneiminato)titanium, [Ti(NPPh3)4] The title compound has been prepared by the reaction of [TiCl2(NPPh3)2] with methyllithium and cyclopentadienyllithium, respectively, in hexane solution. [Ti(NPPh3)4] · 3 C7H8 crystallizes from toluene solution to form colourless, only slightly moisture sensitive crystals which were characterized by a crystal structure determination. Space group I41/a, Z = 8, lattice dimensions at ?80°C: a = b = 2160.7(2), c = 3334.2(3) pm, merohedral (110) twin, R = 0.077. The compound forms monomeric molecules with tetrahedrally coordinate titanium atoms and bonding parameters of TiN = 187.3 pm, PN = 155.1 pm, TiNP 150.4° in average.  相似文献   

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The title compound I (C22H24MnN10S2, Mr = 547.57) has been synthesized and structurally characterized by single-crystal X-ray diffraction. The compound crystallizes in the monoclinic system, space group P2 1/c with a = 8.6010(17), b = 9.0180(18), c = 17.773(4)A, β = 101.79(3)°, V = 1349.5(5)A^3, Z = 2, Dc = 1.348 g/cm^3,/1 = 0.674 mm^-1, F(000) = 566, the final R = 0.0488 and wR = 0.1289. In the structure, each Mn atom is coordinated by four Vim (Vim = 1-vinylimidazole) ligands and a pair of monodentate isothioeyanic groups, affording a compressed oetahedral MnN6 core.  相似文献   

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Introduction In recent years, much attention has been paid to the research of novel, high-quality nonlinear optical (NLO) crystals, especially those metalorganic complex crystals that can generate high efficient second-harmonic blue-violet light using GaAlAs laser diodes. In order to find this type of crystals, much work has been done in our laboratory on the complex crystals of MM'(SCN)4 and MM'(SCN)·nL, where M = Zn, Cd, Mn; M' = Cd, Hg and L = adduct1-6. A 404.5nm blue-violet lig…  相似文献   

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